1. Field of the Invention
The invention relates to helical textiles.
2. Description of the Related Art
One of the primary purposes of helical or spiral shaped material is to reinforce a composite material. Therefore, the fiber selection, fiber orientation and other features of the textile material must be considered to maximize the effectiveness of the textile material as a reinforcement to the final product.
Others have described woven helical fabrics, such as that disclosed in U.S. Pat. No. 5,222,866 that was issued to LaBrouche et al. on Jun. 29, 1993, and which is not admitted to being prior art by its mention in this Background section (the '866 patent). In the '866 patent the yarns in the warp (circumferential direction of the spiral) and yarns in the weft (radial direction of the spiral) are interlaced in the manner used with traditional weaving processes and typical weave designs, such as plain weave, satin weave, and basket weave.
One example is shown in FIG. 1. The interlacings produced in the weaving process are necessary to hold the fabric together, and result in a lack of straightness in the yarns in either or both of the warp or weft directions called crimp. Crimp is introduced at fiber interlacings as illustrated in 106a through 106e between warp yarns 102 and weft yarns 104. The crimp reduces the efficiency of the fibers to translate their properties to the ultimate composite structure or textile material.
Knitting processes can be divided into two categories: warp knitting and weft knitting. Weft knitting results in a textile structure where the yarns are interlocked to adjacent yarns resulting in very tortuous fiber paths. This does not allow for effective reinforcement for high performance composites.
What is needed, therefore, is a helical textile for reinforcing composite materials that does not crimp the fibers, but has uniform thickness, and process for making the same.